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Following Cell-fate in E. coli After Infection by Phage Lambda
06:10

Following Cell-fate in E. coli After Infection by Phage Lambda

Published on: October 14, 2011

Effect of multiplicity of infection on transcription in Escherichia coli cells infected by bacteriophage lambda

K C Luk, K K Mark

    The Journal of General Virology
    |January 1, 1983
    PubMed

    Insights

    Bacteriophage lambda infection of E. coli shows that higher multiplicity of infection (m.o.i.) decreases transcription, especially with the cro gene product. Lowering cro gene expression increases transcription, indicating gene dosage controls expression levels.

    Area of Science:

    • Molecular Biology
    • Microbiology
    • Genetics

    Background:

    • Bacteriophage lambda infection in Escherichia coli is a model system for studying gene regulation.
    • The multiplicity of infection (m.o.i.) can influence viral gene expression and replication.
    • Understanding transcription regulation is crucial for comprehending viral life cycles and host-pathogen interactions.

    Purpose of the Study:

    • To investigate the impact of bacteriophage lambda's multiplicity of infection (m.o.i.) on viral transcription.
    • To elucidate the role of the cro gene product in modulating transcription levels at different m.o.i.s.
    • To determine if gene dosage is a significant factor in controlling bacteriophage gene expression.

    Main Methods:

    • Infection of Escherichia coli with specific bacteriophage lambda mutants (lambda cI47, lambda cI47O29P3, lambda cI857cro27P3).
    • Quantitative analysis of mRNA transcription using DNA-RNA hybridization techniques.
    • Measurement of transcription from different phage regions (l-strand, r-strand early x-P-Q region, late A-J-b2 region).

    Main Results:

    • Increasing m.o.i. of lambda cro+ led to decreased transcription across all studied phage regions.
    • Phage DNA replication, when permitted (lambda cI47), resulted in similar transcription patterns but at higher overall levels.
    • In lambda cI857cro- infections, increasing m.o.i. correlated with increased transcription, with less drastic changes compared to lambda cro+.

    Conclusions:

    • The cro gene product of bacteriophage lambda directly inhibits transcription, causing a decrease at higher multiplicities of infection.
    • Gene dosage is a significant factor controlling the extent of gene expression during bacteriophage lambda infection.
    • The findings provide insights into the regulatory mechanisms governing viral gene expression in response to infection levels.

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